The present invention relates to a process for working up reaction outputs from the hydrogenation of EDDN and/or EDMN. The present invention also relates to the preparation of TETA and/or DETA by conversion of EDDN and/or EDMN, the reaction outputs being separated in accordance with the invention.
The present invention further provides for the preparation of epoxy resins, amides or polyamides from the DETA or TETA worked up in accordance with the invention.
WO 2008/104579 and the prior art cited in WO 2008/104579 specify various preparation methods for EDDN and EDMN.
It is disclosed that these reactions are preferably performed at a temperature of 10 to 90° C. and at standard pressure to slightly elevated super-atmospheric pressure. Preferred reactors are described as being a tubular reactor or a stirred tank cascade. The reaction output formed is preferably worked up by distillation, first removing low boilers such as hydrogen cyanide in a first stage and removing water in a second distillation step. The remaining aminonitrile mixture may have a residual water content of preferably at least 10% by weight.
WO 2008/104553 describes the hydrogenation of EDDN or EDMN with hydrogen in the presence of catalysts. After the hydrogenation, the output from the hydrogenation can optionally be purified further, for example by removing the organic solvent and/or the catalyst by methods known to those skilled in the art. More particularly, the main products (TETA or DETA) can be removed from the reaction product together or individually by methods known to those skilled in the art. If the two main products are isolated together, for example by a distillation, they can subsequently be isolated into the two individual products. Ultimately, pure TETA and pure DETA are thus obtained. Other impurities, by-products or further ethyleneamines such as TEPA or PIP can likewise be removed from the particular product by methods known to those skilled in the art. Optionally, TETA can also be isolated together with diaminoethylpiperazine or piperazinyl-ethylethylenediamine formed in small amounts. The hydrogenation outputs from the hydrogenation of EDDN are preferably worked up by distillation in accordance with the disclosure.